cache.c: read(2) returns -1 on error, not 0

Noticed-by: Jim Meyering <jim@meyering.net>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/cache.c b/cache.c
index b701e13..add647e 100644
--- a/cache.c
+++ b/cache.c
@@ -39,33 +39,33 @@ struct cache_slot {
  * (part of) the content of the cache file. Return 0 on success
  * and errno otherwise.
  */
 static int open_slot(struct cache_slot *slot)
 {
         char *bufz;
         int bufkeylen = -1;
 
         slot->cache_fd = open(slot->cache_name, O_RDONLY);
         if (slot->cache_fd == -1)
                 return errno;
 
         if (fstat(slot->cache_fd, &slot->cache_st))
                 return errno;
 
         slot->bufsize = read(slot->cache_fd, slot->buf, sizeof(slot->buf));
-        if (slot->bufsize == 0)
+        if (slot->bufsize < 0)
                 return errno;
 
         bufz = memchr(slot->buf, 0, slot->bufsize);
         if (bufz)
                 bufkeylen = bufz - slot->buf;
 
         slot->match = bufkeylen == slot->keylen &&
             !memcmp(slot->key, slot->buf, bufkeylen + 1);
 
         return 0;
 }
 
 /* Close the active cache slot */
 static void close_slot(struct cache_slot *slot)
 {
         if (slot->cache_fd > 0) {